] Nanocrystalline silicon and carbon nanotube nanocomposites ..pdf

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1、PureAppl.Chem.,Vol.80,No.11,pp.2513–2520,2008.doi:10.1351/pac200880112513©2008IUPACNanocrystallinesiliconandcarbonnanotubenanocompositespreparedbypulsedlaserfragmentation*VladimirSˇvrcˇek‡ResearchCenterforPhotovoltaics,NationalInstituteofAdvancedIndustrialScienceandTechnology(AIST)Cen

2、tral2,1-1-1Umezono,Tsukuba,Ibaraki,305-8568,Japan,andNanoarchitectonicsResearchCenter,AIST,Central5,1-1-1Higashi,Tsukuba,Ibaraki3058565,JapanAbstract:Thispaperoutlinesthesynthesisofnanocrystallinesilicon(nc-Si)bynanosecondpulsedlaserfragmentationofSimicrograinsinliquidsolutions,andcha

3、racterizationoftheproducts.Wecomparemicrograinfragmentationsindeionizedwater,andinundopedandphosphorus-dopedethylpolysilicate(C2H5O[SiO(C2H5O)2]nC2H5)basedpolymers.Weshowthatdissolutionandsubsequentlaserfragmentationofmicrograinsismoreefficientinbothpolymericmediathaninwater.Inthecase

4、ofwater,micrograinsurfacewettingbyethanolpriortointroductionintowaterisessentialtoachievefragmentation.Preparednc-Si/polymernanocompositesdisplayvisiblephotoluminescence(PL)(~430nm)atroomtemperature.ThephosphoruspolymerinducesablueshiftofthePLpeak.Inaddition,in-ducedshockwavesgenerate

5、datsufficientlyhighlaserirradiationintensities(>4.3mJ/pulse)causecarbonnanotube(CNT)cavitiestobefilledbyfreshlypreparedluminescentnc-Si/polymernanocomposite.Keywords:siliconnanocrystals;photoluminescence;laserablation;carbonnanotubes.INTRODUCTIONThepossibilityofencapsulatingnanocrysta

6、llinemoleculesinsidethecavityofcarbonnanotubes(CNTs)isopeningupnewroutestoengineerandtunetheelectronicpropertiesofsuchnewnano-compositematerials[1].Ontheotherhand,anobservationofvisiblephotoluminescence(PL)innano-crystallinesilicon(nc-Si)[2]wasgreetedwithgreatinterest[3,4].Controlofop

7、ticalresponsebymod-ifyingthesizeorsurfacechemistryofSinanocrystalshasbecomeoneofthemostchallengingaspectsofrecentsemiconductorresearch[5].However,thehighsurfacetensionofmoltenSimakesdirectfill-ingofaCNTcavityimpossible[6].Thischallengecanbeovercomebyusingnc-Sidispersedinsolu-tions,whi

8、choff